Steel conversion apparatus

ABSTRACT

An open topped vessel for converting molten ferrous metal to steel is pivotable about a horizontal axis and has bottom tuyeres which permit the blowing of oxygen or other gases upwardly through the molten metal. An enclosure at least partially surrounds the vessel and co-operates with a smoke hood to prevent the escape of pollutants when the vessel is in its vertical position. Suction means is coupled to the hood for creating an in-draft at a closable access opening to prevent the release of pollutants when the vessel is pivoted to place its open top adjacent the access opening for receiving a charge.

United States Patent [1 1 Baum et al.' July 3, 1973 [54] T E CONVERSIONAPPARATUS 3,205,810 9/l965 Rosenak zoo 3s ,014, 5 l l96l B a V [75]Inventors: Jeorg P. Baum, Essen, Germany; 3 2 5 2, ussard a] 266] grDortenzo Plttsburgh Primary Examiner-Gerald A. Dost Attorney-Wiviott &Hohenfeld't [73] Assignees: Pennsylvania Engineering Company,

Pittsburgh, Pa.; Verfahrenstechnik [57] ABSTRACT Essen Germany An opentopped vessel for converting molten ferrous [22] Filed: July 26, 1971metal to steel is pivotable about a horizontal axis and i has bottomtuyeres which permit the blowing of oxygen 2] App]. No.. 165,920 orother gases upwardly through the molten metal. An enclosure at leastpartially surrounds the vessel and co [52] U.S. Cl 266/36 P, 266/15operates with a smoke hood to prevent the escape of [51] Int. Cl. C21c5/38 pollutants when the vessel is in its vertical position. [58] Fieldof Search 266/13, 34 V, 35, Suction means is coupled to the: hood forcreating an 2615/36 P, 15 in-draft at a closable access opening toprevent the release of pollutantsv when the vessel is pivoted to place[56] ReferencesCited its open top adjacent the access opening forreceiving UNITED STATES PATENTS a charge- 2,803,450 8/1957 McFeaters266/35 16 Claims, 2 Drawing Figures Patented July 3, 1973 3,743,264

INViENTORS ALEXANDER T. DORTENZO JEORG P BAUM ATTOR NEYS STEELCONVERSION APPARATUS BACKGROUND OF THE INVENTION The objectives ofmodern steel plant designs are to reduce operating costs, capitalinvestment and pollution that is incidental to the process. Considerableprogress has been made in improving efficiency and reducing causes ofpollution by use of various conversion vessels. These include the basicoxygen converter, the argon-oxygen converter and the bottom blownconverter. Each of these converters generally comprises a vessel whichis open at its upper end. Such vessels are normally oriented verticallybut are rotatable about a horizontal axis so that they may be tilted forcharging hot metal and scrap through an open upper end and for teemingor deslagging, temperature measurement and sampling.

Certain prior art converter systems employ a smoke hood located directlyabove the open upper end of the vessel when the latter was in itsupright position. However, when such vessels were tilted, their openupper ends were displaced from the smoke hood so that the latter can noteffectively prevent pollutants from being discharged into thesurrounding atmosphere.

in basic oxygen converters, the oxygen is introduced into the vessel bymeans of a lance extending downwardly through the open upper end. In theargonoxygen converter vessel and the bottom blown converters the oxygenor other gases are introduced through tuyeres located below the level ofmolten metal. When the basic oxygen converters were tilted to receivehot metal-and scrap, for example, the oxygen lance was normally off.This was also possible in argon-oxygen converters where the tuyeres arelocated in the sides of the vessels so that they would be free of metalwhen the vessel is tilted. In the bottom blown converter, however, wherethe .tuyeres are located in the vessels bottom, gas flow must bemaintained at all times to prevent the backup of hot metal through thetuyeres and into the gas system. This further complicates the control ofpollutants when the bottom blown vessel is in its tilted position.

SUMMARY OF THE INVENTION A general object of the invention is to providea new and improved pollution control apparatus for steel conversionvessels.

Another object of the invention is to provide apparatus for preventingthe discharge of pollutants from steel conversion vessels when thelatter are in each of their various alternate positions.

A further object of the invention is to provide apparatus for preventingthe discharge of pollutants into the surrounding atmosphere from a steelconversion vessel when the latter is being charged, sampled, deslaggedor during teeming.

These and other objects and advantages of the present invention willbecome more apparent from the detailed description of the preferredembodiment taken with the accompanying drawings. In general terms, theinvention comprises a converter vessel having an open upper end, anenclosure substantially surrounding the vessel and having an accessopening to permit hot metal or scrap to be charged into the vessel, anda gas withdrawal system for creating an indrat't through the accessopening to prevent the outflow of polluting gases from the enclosure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view,partly in section, of a converter vessel and pollution control systemaccording to the present invention; and

FIG. 2 shows an alternate embodiment of the apparatus of FIG. 1 with theconverter vessel in an alternate position.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention will beillustrated and discussed with respect to a bottom blown conversionvessel 10 shown in FIGS. 1 and 2 although those skilled in the art willappreciate that it has application as well to other types of converterssuch as basic oxygen and argon-oxygen systems.

The vessel 10 is open at its upper end and includes a metallic shell 11and a refractory lining 12. A plurality of tuyeres 13 are formed throughthe lower end of the vessel to permit the injection of gasesby meanswhich will be described more fully below. As those skilled in the artwill appreciate, conversion vessels of this type are generally supportedin a conventional manner on a trunnion ring 14 which has a trunnion 15extending from each of its opposite sides. The trunnions 15 are suitablysupported in a well-known manner on bearing structures (not shown)-andare coupled to a suitable drive mechanism (not shown) for tilting vessel10 to each of a plurality of positions as may be required during aprocess cycle.

Referring now specifically to the embodiment of FIG. 1, the vessel 10 isshown to be disposed within a metallic enclosure 16 having a top wall 17disposed above the open upper end of vessel 10 and side walls 18extending downwardly from the top wall 17 to substantially ground level.While the enclosure 16 is shown in FIG. 1 to be generally rectangular inhorizontal crosssection and the cover 17 is shown to be generally frus'to-pyramidal, it will be appreciated that the enclosure portions maytake any convenient shape.

A top opening 20 is formed in cover l? for receiving a smoke hood 21which normally engages the open upper end of vessel 12 when the latteris in its vertical position shown in FIG. 1. Smoke hood 21 may include aconical collar section 22 for engaging the upper end of the vessel 10and a generally cylindrical section 24 which extends upwardly throughopening 20. A smaller cylindrical section 25 extends upwardly fromsection 24 for telescoping engagement withthe lower end of a dischargepipe 26. The smoke hood assembly 21 is sup ported from a fixed member 28by threaded shafts 29 which engage suitable fixed nut members (notshown) on hood 21. A drive assembly (not shown) rotates threaded shafts29 so that the hood assembly 21 may be moved between its vessel engagingposition shown in FIG. 1 and its elevated position shown in FIG. 2. Itwill be appreciated that section 24 and margins of opening 20 andtelescoping members 25 and 26 will be constructed and arranged to remainin a substantially sealed relation when the smoke hood is in its variouspositions.

A charge opening 30 is formed at one side of top wall 17 and an accessdoor 31 is suitably mounted thereon for sliding movement between openand closed positions relative to opening 30. In addition, one or moreaccess openings 32 and 33 may be formed in the lower end of side walls18 to permit movement of a transfer car 34 into and out of enclosure 16on rails 35. The transfer car may be employed to position a slag pot 36or a teeming ladle 37 beneath the vessel as may be required. Doors 38and 39 may be suitably mounted on walls 18 for movement between open andclosed positions relative to openings 32 and 33 respectively when theposition of transfer car 34 permits.

As indicated above, the conversion vessel illustrated in FIGS. 1 and 2is of the bottom blown type having tuyeres 13 which extend through thelower end of vessel 10 and through which suitable gas pipes 40 extend.The other end of pipes 40 engage a manifold 42 disposed in a chamber 43mounted on the bottom of vessel 10. Manifold 42 is coupled by pipe 44 toreceive gases or other material which are to be injected into the hotmetal vessel 10. For a more complete description of the process whichmay be employed in vessel 10, reference is made to co-pendingapplication Ser. No. 163,591, filed July 19, 1971, and which is assignedto one of the assigness of the instant invention.

An auxiliary suction system 48 may be coupled to an opening 49 formed inthe top wall 17 of enclosure 16 at a point above access opening 30. Anauxiliary hood 50 is secured to top wall 17 in surrounding relation toopening 49 and is coupled by a conduit 51 to the suction system (notshown).

FIG. 1 illustrates the normal operating position of the vessel 10. Herethe vessel is shown to be disposed generally vertically with the smokehood assembly 21 in position over the vessels open upper end. Treatmentgases and other materials are injected through the tuyeres beneaththemolten metal which may be disposed in the vessel 10 up to height 53. Asthose skilled in the art will appreciate, it becomes necessary from timeto time during the treatment cycle to rotate the vessel 10 onthetrunnions 50. Toward this end, the smoke hood assembly 21 is firstelevated from its position shown in FIG. 1 to that shown in FIG. 2wherein the collar 21 is elevated relative to the upper end of vessel10. The engagement between the cylindrical section 24 and the opening 20maintains the latter in a substantially closed condition. When theassembly 21 has been fully elevated, a shoulder 55 formed at thejunction between the portion 24 and collar 22 will abut the lowersurface of the top wall 17. The assembly 21 will therefore remaineffective to withdraw pollutants without substantial leakage throughopening 20. If, for example, the vessel 10 is tilted for the purpose ofsampling the hot metal or charging the vessel 10 with additional hotmetal or scrap, the vessel is pivoted in a counterclockwise directionuntil its open upper end is adjacent access opening 30. The door 31 maythen be opened and a charging chute 56, for example, inserted intoproximity with the vessel opening. The charging of hot metal or scrapnormally causes a substantial quantity of gaseous and particulatepollutants to be generated within the vessel. This condition isaggravated by the fact that the gas supply to vessel 10 must continuewhile the vessel is tilted so as to prevent a back flow of molten metalinto the tuyeres l3 and the gas supply systern.

The auxiliary suction system 48 which is positioned above the accessopening 30 is operative to cause a slight negative pressure within theenclosure 16 at the opening 30 to cause an inflow of outside air. Thisprevents the egress of the gaseous and particulate pollutants fromenclosure 16 but instead causes them to flow into the auxiliary suctionsystem 48 and the main suction system 21. It has been found in actualpractice that the main and auxiliary suction systems must function tocreate a flow velocity of from 1,000 to 2,000 feet per minute at theopening 30 to prevent the escape of pollutants from the enclosure 16. Itis also preferable that hood 50 of the auxiliary system be as close tothe opening 30 as possible to maximize its effectiveness.

It may also be necessary, from time to time, to discharge slag from thevessel 10 into the slag pct 36 to pour the hot metal into the ladle 37.This is accomplished by first elevating the smoke hood assembly 21 inthe manner indicated above and then rotating the vessel clockwise fordischarging slag or hot metal into the appropriate ones of thecontainers 36 or 37 and through a pouring a spout 57. During thisoperation, the access door 31 remains in its closed position. Hereagain, the main and auxiliary exhaust systems 21 and 48 are effective toprevent the discharge of pollutants from enclosure 16.

FIG. 2 also illustrates an alternate embodiment of the invention whereinthe enclosure 16' terminates at a point above the floor level. However,because substantially all of the gaseous and particulate pollutants tendto rise as a result of the intense heat generated in the vessel 10,substantially none escapes around the lower edge of the enclosure 16. Onthe contrary, a chimney effect is created wherein outside air is drawnbelow the lower marginal edge of enclosure 16 for discharge through theexhaust system.

The pollutants removed from enclosures 16 and 16 through the suctionsystems according to the invention are treated in conventional gasscrubbing and cleaning apparatus which need not be described here.

It will be appreciated that the pollution control assembly according tothe present invention prevents the discharge of particulate and gaseouspollutants from the vessel 10 both when it is in its upright operativeposition and when it is tilted such as for charging, sampling,deslagging, teeming and the like. Also, while the invention has beendescribed with respect to one type of converter vessel, it will beappreciated that it may be applicable to other types of convertingvessels as well. Further, while only a single configuration has beenillustrated with respect to the enclosures 16 and 16 they may take anyconvenient shape without deviating from the inventive concept.Accordingly, it is not iritended that the invention be limited to theforegoing description, but only by the scope of the appended claims.

We claim:

1. A converter vessel having a metal receiving opening formed adjacentan upper end thereof,

an enclosure substantially surrounding said vessel and having meansdefining an upper wall portion disposed above said vessel and a sidewall portion extending generally downwardly from said upper" wallportion, an access opening formed in one of said wall portions,

said upper and side wall portions being disposed in a closelysurrounding relation to said vessel,

said vessel being adapted to be tilted about a substantially horizontalaxis to position said metal receiving opening adjacent said accessopening so that said vessel may be charged,

and exhaust means including means extendingthrough said upper wallportion and engageable with said metal receiving opening when saidvessel is in an untilted position for withdrawing pollutants generatedin said vessel, said exhaust means also being operative to create anin-draft at said access opening to prevent the escape of said pollutantswhen said vessel is tilted in its metal receiving position.

2. The invention set forth in claim 1 wherein said enclosure is open atits lower end and terminates at substantially the lower end of saidvessel.

3. The invention set forth in claim 1 wherein said enclosure issubstantially closed at its lower end and extends a substantial distancebelow said vessel.

4. The invention set forth in claim 1 wherein said metal receivingopening is normally disposed in a first position spaced from accessopening, said exhaust means including first exhaust means disposed abovesaid first position.

5. The invention set forth in claim 1 and including closure means fornormally closing said access opening.

6. A converter vessel having a metal receiving opening,

an enclosure substantially surrounding said vessel and having an accessopening formed therein, said metal receiving opening normally beingdisposed in a first position spaced from said access opening,

said vessel being adapted to be tilted about a substantially horizontalaxis to position said metal receiving opening adjacent said accessopening so that said vessel may be charged,

and exhaust means connected to said enclosure for withdrawing pollutantsgenerated in said vessel and for creating an in-draft at said accessopening to prevent the escape of said pollutants when said vessel istilted in its metal receiving position,

said exhaust means including first exhaust means disposed above saidfirst position and second exhaust means disposed above said accessopening.

7. The invention set forth in claim 4 wherein said first exhaust meansincludes a hood means which is movable into and out of engagement withsaid vessel for surrounding said metal receiving opening.

8. The invention set forth in claim 7 wherein said exhaust meansincludes a second exhaust means disposed above said access opening.

9. The invention set forth in claim 8 and including door means fornormally closing said access opening.

10. The invention set forth in claim 8 wherein a first exhaust openingis formed in said enclosure for receiving said first exhaust means, saidfirst exhaust means substantially closing said opening when in each ofits engagement and out of engagement positions relative to said opening.V

111. The invention set forth in claim 10 wherein said enclosure includesa second exhaust opening formed therein above said access opening, saidsecond exhaust means including means surrounding said second exhaustopening.

12. The invention set forth in claim 11 wherein said enclosure is openat its lower end and terminates at substantially the lower end of saidvessel.

13. The invention set forth in claim 11 wherein said enclosure issubstantially closed at its lower end and extends a substantial distancebelow said vessel.

14. A method of controlling the discharge of pollutants from an opentopped vessel containing hot metal wherein gases are introduced intosaid metal through tuyeres located in the lower end of said vessel, thesteps of,

surrounding at least the top and sides of said vessel with an enclosure,

positioning a first exhaust means in a surrounding relation to the opentop of said vessel when the latter is in a substantially verticalposition,

raising said first exhaust means away from said vessel,

tilting said vessel to position its open top adjacent an access openingin said enclosure and displaced from said first exhaust means,

creating an in-draft through said access opening to prevent thedischarge of pollutants, and

charging said vessel through said access opening,

and collecting at least a portion of said pollutants by second exhaustmeans located over said access opening. 15. The method set forth inclaiml4 and including the steps of returning said vessel to its verticalposition and closing said access opening. I 16. A converter vesselhaving a metal receiving opening,

an enclosure substantially surrounding said vessel and having meansdefining a roof portion disposed above said vessel'and a side wallportion extending generally'downwardly from said roof portion,

means defining an access opening formed in one of said wall portions,

means mounted on said enclosure for selectively opening and closing saidaccess opening,

said vessel being adapted to be tilted about a substantially horizontalaxis to position said metal receiving opening adjacent said accessopening so that said vessel may be charged,

first exhaust means extending through said roof portion for engagingsaid metal receiving opening when said vessel is in an untilltedposition and second exhaust means disposed above said access opening,said first and second exhaust means being operative to prevent theescape of pollutants when said vessel is tilted in its metal receivingposition.

i i t i i"

1. A converter vessel having a metal receiving opening formed adjacentan upper end thereof, an enclosure substantially surrounding said vesseland having means defining an upper wall portion disposed above saidvessel and a side wall portion extending generally downwardly from saidupper wall portion, an access opening formed in one of said wallportions, said upper and side wall portions being disposed in a closelysurrounding relation to said vessel, said vessel being adapted to betilted about a substantially horizontal axis to position said metalreceiving opening adjacent said access opening so that said vessel maybe charged, and exhaust means including means extending through saidupper wall portion and engageable with said metal receiving opening whensaid vessel is in an untilted position for withdrawing pollutantsgenerated in said vessel, said exhaust means also being operative tocreate an in-draft at said access opening to prevent the escape of saidpollutants when said vessel is tilted in its metal receiving position.2. The invention set forth in claim 1 wherein said enclosure is open atits lower end and terminates at substantially the lower end of saidvessel.
 3. The invention set forth in claim 1 wherein said enclosure issubstantially closed at its lower end and extends a substantial distancebelow said vessel.
 4. The invention set forth in claim 1 wherein saidmetal receiving opening is normally disposed in a first position spacedfrom access opening, said exhaust means including first exhaust meansdisposed above said first position.
 5. The invention set forth in claim1 and including closure means for normally closing said access opening.6. A converter vessel having a metal receiving opening, an enclosuresubstantially surrounding said vessel and having an access openingformed therein, said metal receiving opening normally being disposed ina first position spaced from said access opening, said vessel beingadapted to be tilted about a substantially horizontal axis to positionsaid metal receiving opening adjacent said aCcess opening so that saidvessel may be charged, and exhaust means connected to said enclosure forwithdrawing pollutants generated in said vessel and for creating anin-draft at said access opening to prevent the escape of said pollutantswhen said vessel is tilted in its metal receiving position, said exhaustmeans including first exhaust means disposed above said first positionand second exhaust means disposed above said access opening.
 7. Theinvention set forth in claim 4 wherein said first exhaust means includesa hood means which is movable into and out of engagement with saidvessel for surrounding said metal receiving opening.
 8. The inventionset forth in claim 7 wherein said exhaust means includes a secondexhaust means disposed above said access opening.
 9. The invention setforth in claim 8 and including door means for normally closing saidaccess opening.
 10. The invention set forth in claim 8 wherein a firstexhaust opening is formed in said enclosure for receiving said firstexhaust means, said first exhaust means substantially closing saidopening when in each of its engagement and out of engagement positionsrelative to said opening.
 11. The invention set forth in claim 10wherein said enclosure includes a second exhaust opening formed thereinabove said access opening, said second exhaust means including meanssurrounding said second exhaust opening.
 12. The invention set forth inclaim 11 wherein said enclosure is open at its lower end and terminatesat substantially the lower end of said vessel.
 13. The invention setforth in claim 11 wherein said enclosure is substantially closed at itslower end and extends a substantial distance below said vessel.
 14. Amethod of controlling the discharge of pollutants from an open toppedvessel containing hot metal wherein gases are introduced into said metalthrough tuyeres located in the lower end of said vessel, the steps of,surrounding at least the top and sides of said vessel with an enclosure,positioning a first exhaust means in a surrounding relation to the opentop of said vessel when the latter is in a substantially verticalposition, raising said first exhaust means away from said vessel,tilting said vessel to position its open top adjacent an access openingin said enclosure and displaced from said first exhaust means, creatingan in-draft through said access opening to prevent the discharge ofpollutants, and charging said vessel through said access opening, andcollecting at least a portion of said pollutants by second exhaust meanslocated over said access opening.
 15. The method set forth in claim 14and including the steps of returning said vessel to its verticalposition and closing said access opening.
 16. A converter vessel havinga metal receiving opening, an enclosure substantially surrounding saidvessel and having means defining a roof portion disposed above saidvessel and a side wall portion extending generally downwardly from saidroof portion, means defining an access opening formed in one of saidwall portions, means mounted on said enclosure for selectively openingand closing said access opening, said vessel being adapted to be tiltedabout a substantially horizontal axis to position said metal receivingopening adjacent said access opening so that said vessel may be charged,first exhaust means extending through said roof portion for engagingsaid metal receiving opening when said vessel is in an untilted positionand second exhaust means disposed above said access opening, said firstand second exhaust means being operative to prevent the escape ofpollutants when said vessel is tilted in its metal receiving position.